Physical Science Lab #5

Physical Science lab #5

Objective

The goal of this experiment is to develop a theory, which allows us to understand the motion of a marble.

Materials

Wooden roller coaster, marble, ruler, timer, clamp, physics stand.

Theory

In this experiment, we are finding the Conservation of Energy. Energy is neither created nor destroyed. Energy is summed up into two different properties: Potential energy and Kinetic energy. The law of Energy states that:

Total Energy = Potential Energy + Kinetic Energy Or Em = Ep + Ek

Also, the equations for Potential energy and Kinetic energy are stated to get the Total Energy. They are respectively:

Ep = mgh and Ek = ½ (m)v2

The Conservation of Energy states that energy is always constant. If potential energy increases then kinetic energy decreases and vice versa. In this experiment we positioned a marble ball on a wooden roller coaster positioned on a physics stand in the sixth hole. Throughout the experiment, we used an electronic timer to record the time of the marble where it passed through the light beam of its clamp. We positioned the clamp at a certain point on the roller coaster and measured the distance from the marble to the clamp; the height of the clamp; and finally the time the ball traveled through the clamp. After we recorded these different figures we calculated the speed of the marble from the given distance traveled and the time. We repeated the step 14 times, then proceeded to graph the speed and the height. Next, we took the measurements of position of the clamp, height, and speed and calculated the potential energy, the kinetic energy, and the total energy. Total energy calculated as mentioned before. Potential energy is taking the mass (m) which is 28.1g times gravity (g) which is 9.8 m/s2 times the height. Kinetic energy is one-half times the mass (m) times velocity (v2). Finally we graphed the calculated kinetic, potential, and total energies of this experiment. For this theoretical result, the motion or speed of the marble will have different calculations. Also, the potential energy and kinetic energy of the marble will produce a mirror effect between each other respectively. From the result of the experiment, as the height of the marble increases the speed of the marble decreases at a slow rate.

Data

See attached documents.

Calculation

1) Speed of the Marble: Speed = distance traveled by marble / time from clamp A

2) Potential Energy: Ep = mgh

3) Kinetic Energy: Ek = ½(m)v2

4) Total Energy: Em = Ep + Ek

Error Analysis

There was no apparent error analysis.

Questions and Answers

1) Watch the marble roll along the track. At which place (or places) shown in the picture do you think the marble moves the fastest? Why?

Answer: The marble moves fastest at point 2 and point 6. Because the kinetic energy of the marble is greater than any other point on the roller coaster.

2) What did you notice about the motion of the marble from the measurements? For example, does the direction of motion (up or down) seem to have a large effect on the speed? Does height affect speed?

Answer: As the distance of the clamp moved farther from the marble, the time became more varied and unpredictable throughout the experiment. Yes, the direction of motion seems to have a large affect on the speed. Yes, height does affect speed.

3) What conclusions can be drawn from your graph #1?

Answer: In graph #1, the speed throughout the experiment was constantly decreasing as the height was increased.

4) From your graph #2, what can you say about the energy of the marble?

Answer: The potential energy of the marble started off high and as it progressed through the experiment, dropped then rose then ended at a lower point. The kinetic energy of the marble started off low and then rose its energy then dropped again and finally ended at a higher point. The total energy of the marble started high, dropped slightly then rose slightly and finally evened off to a mid-point but lower than when it started.

5) How can you use energy conservation to predict the speed of the marble from the height?

Answer: By measuring the distance traveled of the marble and determines the speed. As the kinetic energy of the marble increases, the potential energy of the marble decreases.

6) What percentage of the marble's energy is left at the end of the roller coaster just before it stops (or the last place you measured)?

Answer: The percentage where the potential and the kinetic energy's interact each other is where the marble's energy is left at the end of the roller coaster.

7) What happens to the lost energy of the marble?

Answer: With the lost energy of the marble, the energy has become non-existent when it stops.